Notez [tex]x^{2}+x+1=a\\
\\ inlocuiesc:\\
\\ 1+(a+2)\cdot a=(a+1)^{2}\\
\\ ( 1+(x^{2}+x+1+2)\cdot (x^{2}+x+1)=(x^{2}+x+1+1)^{2} )\\
\\ \\
\\ 1+a^{2}+2a=(a+1)^{2}\\
\\ ( 1+(x^{2}+x+1)^{2}+2(x^{2}+x+1)=(x^{2}+x+1+1)^{2} )\\
\\ \\
\\ (a+1)^{2}=(a+1)^{2}~(A)\\
\\ ( (x^{2}+x+1+1)^{2}=(x^{2}+x+1+1)^{2}~(A) )[/tex]